Home      Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science

<< Back to INDEX

Police Siren Circuit using NE555 Timer [Project]
posted March 21 2014 4:01.14 by spic0m

This circuit produces a sound similar to the police siren. The two 555 act as an astable multivibrator. The 555 timer IC is an integrated circuit used in a variety of timer, pulse generation and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element.In the beginning 555 is coupled like a low-frequency oscillator so to command the voltage at the second 555 IC at pin 5 which is a control pin.The shifting of the voltage on pin5 is the root of the second oscillator frequency to get up and down.

Police siren circuit which is explained here is worked on NE555 timer IC. The circuit is build with the help of two NE555 IC(i.e. IC1 andIC2) which is the basic block of this circuit. Both the timer IC in these circuit is connected like a astable multivibrator. Although both the IC in the circuit work at two dissimilar frequency.IC1 is a astable multivibrator of slow frequency work on frequency of 20HZ and having 50% of duty cycle while IC2 is a fast astable multivibrator works on frequency of 600Hz. IC1 output is then serve to IC2 at the control pin(oin5). Through the help of this arrangement IC2 output frequency will be modulated with the IC1output frequency. The circuit works on the DC supply between a range of 6V to 15V.

The frequency range of the siren can vary with the exchange of R2 and R4 resistor with potentiometer. The pitch of sound can be enlarged with the attachment of the power amplifier at the output point. The accurate effect of police siren can be produced by connecting flashing LEDs at the correct place. The circuit can be made on a Perfboard. NE556 can be used in the place of two NE555.

[Link: Electronicshub.org]

 Share Tweet

You might also like...

 Nine more impressive and clever household hacks [Lifehacks] Pickit 2 clone The Universal Microchip PIC Programmer /Debugger [Project] A coin flipping catapult? For what? Silkscreen or Soldermask for Text on PCB? [PCB Design] DIY Wooden Work Light is Bright and Brilliant [Project] Hacking a salvaged Vacuum Fluorescent Display Arduino based "Etch A Sketch" Laser Cutter [Project] 50W Adjustable Boost Converter Explained [Circuit]

<< Back to INDEX

Comments

 Name  Email (shall not be published)  Website Notify me of new posts via emailWrite your comments below:BEFORE you post a comment:You are welcome to comment for corrections and suggestions on this page. But if you have questions please use the forum instead to post it. Thank you.

 No comment yet...Be the first to comment on this page!

 Contact     Forum     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science     RSS    Site design: Giorgos Lazaridis © Copyright 2008 Please read the Terms of services and the Privacy policy